Process for the introduction of aryl groups into alpha-beta-unsaturated carbonyl compounds and their derivatives



Patented Aug. 11, 3942 PROCESS FOR THE HITRODUCTION OF ARYL GROUPS INTD u-fl-UNSA'EURATED CARBONYL COMPOUNDS AND THEIR DE- RWATIWES Hans Meerwein, Maribor-on-the-Lahn, Germany, asslguor, by mesne assignments, to Sherka Chemical Company, Inc., Bloomfield, N. 1., a

corporation of New York No Drawing. Application September 16, 1936, Serial No.- 101,081. Renewed July 7, 1939. In Germany September 17, 1935 8 Claims.

This invention relates to a process for the introduction of aryl groups into (r p-unsaturated carbonyl compounds and their derivatives.

In accordance with the present invention a-punsaturated carbonyl compounds, such as 5- uusaturated aldehydes, ketones and carboxylic acids and also their derivatives in so far as they contain a hydrogen atom on the carbon atom adjacent the carbonyl group, are reacted with aromatic diazo compounds in such a manner that in the course of the reaction the nitrogen is split oil while the hydrogen atom adjacent the carbonyl group is replaced by the aryl group which is the basis or the diazo compound. It is possible in this manner to introduce an aromatic residue into the said unsaturated compounds.

According to the invention there are obtained,

for example, from benzal acetone with diazo com- CsHs-CH=CH-COaH+Aryl'N-.Cl

CeHt'CH=CH-Ary1+N2+I-IC1+CO2 In the application of aryldiazonium haloids there are produced in individual cases, as, 'for example, by the action of p-chlorobenzene diazonium chloride on benzal acetone, instead of the arylated a-p-unsaturated carbonyl compounds their hydrogen halide addition products from which only by subsequent treatment with agents splitting oiji hydrogen halide, for example, by heating with sodium acetate in glacial acetic acid, are the arylated unsaturated carbonyl com- Pounds obtained.

Instead of the diazo compounds such comverted into diazo compounds, for example, acylnitrosamines oi the formula Aryl-N(COR)NO.

The reaction takes place according to the nature of the components employed between 10 and 40 C. with practically quantitative splitting oil of the nitrogen. An addition of copper or copper salts favours the course of the reaction to an extraordinary degree.

The reaction can be carried out in strong acetic acid, aqueous alcoholic or aqueous acetone solution with the addition of alkali acetates or alkali salts of other weak acids, for example, the salts of the carboxylic acids to be arylated. There can also find application, however, solvents not miscible with water such as methylene chloride. acetylene tetrachloride and others. The presence of negative substituents in the diazo compound favours the course of the reaction.

In German Patent No. 508,395 a process is described for the manufacture of nuclear substituted quinones. wherein aromatic diazo compounds are allowed to react on quinones (compare also Kvalnes, Journal of the American Chemical Society, 56, 2478, (1934) Wieland, Ann. 415, 157 (1934)). The quinones are distinguished, however, as is known. by numerous addition and substitution reactions to such a far- 1 reaching extent from the a-p-unsaturated carbonyl compounds without quinone character that it could not be foreseen on the basis oi. the behaviour oi the quinones with respect to aromatic diazo compounds that also a-p-unsaturatecl carbonyl compounds without quinone character would react with diazo compounds with the introduction of aryl groups.

The following examples illustrate the invention:

Example 1 A solution or p-nitrobenzene dlazonlum chloride, prepared from 6.9 grams of p-nitraniline o mol), 20 grams or 25% hydrochloric acid, 20 grams oi ice and 3.6 grams of sodium nitrite in 7.2 cos. of water is introduced without further cooling all at once into a solution of 6.7 grams of cumaiin 2 mol), in 40 cos. of acetone in which 11 grams of crystallised sodium acetate are suspended. To the mixture is added with brisk stirring a solution of 0.5 gram of copper sulphate in 10 cos. of water. The nitrogen evolution takes place immediately and is complete after 1 hour; the temperature of the reaction mixture is maintained at about 19 C. In time the mixture becomes colored'dark brown and at the pounds can also be employed as are easily consame time there separates a crystallin precipitate. After completion of the reaction the acetone is driven oil with steam, the brown colored crystalline mass filtered with suction and for removal' of unattacked cumarin ground with 30-40 ccs. of acetone. There is obtained practically pure 3-p-nitrophenyl-cumarin in good yield. By recrystallisation from pyridine or anisol it is obtazined in the form of yellow needles of M. P. 2 4 C. i

In a similar manner by the interaction of the diazo compounds from p-chloraniline, ,o-naphthylamine, p-amino benzoic acid and sulphanllic acid are obtained the 3-p-chlorophenyl-cumarin. S-B-naphthyl-cumarin. 3 phenyl cumarin-4'- carboxylic acid and 3-phenyl-cumarin-4'-sulphonic acid.

Example 2 A solution of p-chlorobenzene diazonium chloride (A mol) prepared from 32 grams of p-chloraniline, 100 grams of 25% hydrochloric acid, 100 grams or ice and 18 grams of sodium nitrite in 36 ccs. of water. is introduced into a solution of 37 grams of cinnamic acid (Y4 mol) in 200 cos. of acetone in which 55 grams of crystallised sodium acetate are suspended. The temperature of the mixture amounts to 20 C. There is added a solution of 15 grams copper sulphate in 50 cos. of water, whereupon after about minutes a brisk evolution of nitrogen and carbon dioxide sets in. By external cooling the temperature is maintained at 24-25 C. After 3 hours the reaction is complete.

Thereupon the acetone is blown oil with steam, the brown colored crystalline residue filtered with suction and for destruction of a complex Cu-salt which disturbs further working. up stirred with possible quantity of glacial acetic. acid and the a-acetyi-p-chloro stilbene filtered with suction.

By recrystallisation from benzine it is obtained in the form of yellowish lustrous leaflets oi'M. P. 105-l06 C. It dissolves in concentrated sulphuric acid with an intense yellow color which on gentle warming becomes-emerald green.

ride (V4 mol), prepared from 32 grams of pchloraniline, 100 grams or hydrochloric acid and 18 grams of sodium nitrite in 35 cos. of water. is'added to a solution 01 33 grams or cinnamic aldehyde (V mol) in 200 grams or acetone in which 55 grams of crystalline sodium acetate are suspended. The temperature or the mixture mounts to 17' 0. Then there is further added a solution or 15 grams or copper sulphate in 50 ccs. or water whereupon nitrogen evolution sets in immediately. By cooling, the temperature or a mixture of 10 ccs.'ot 15% hydrochloric acid and 700 ccs. of ether for 1% hours. The whole is filtered from small quantities oi a yellow copper salt, the ethereal solution separated of! and shaken twice for removal of unattached cinnamic acid and small quantities of chlorophenyl cinnamic acid with a total of 200 ccs. 01' normal ammonia solution. Any p-chloro stilbene crystallizing out is brought into solution by the addition of ether. From the ethereal solution by evaporation p-chloro stilbene is obtained which after recrystallisation from glacial acetic acid or benzine is produced in the form of colorless leatlets of melting point 127.5-128.5 C. With crotonic acid there is obtained chiefly a-(p-chlorophenyD-crotonic acid, but also carbon dioxide splitting and formation of p-chloro-prqp nyl benzene can be observed.

Example 3 A solution of p-chlorobenzene diazonium chloride (A mol) prepared as in Example 2 is added to a solution or 36.5 grams of benzal acetone (Y4 .mol) in 200 cos. of acetone in which 110 grams) of crystallised sodium acetate are suspended.

' product taken up in ether, the ethereal solution washed consecutively with water, ammonia and dilute acetic acid and the ether distilled oil. The residue is for splitting of! 01 the added hydrochloric acid heated to boiling for half an hour with a solution or 45 grams of anhydrous sodium acetate in 180 ccs. or glacial acetic acid and the.

reaction mixture poured on ice. The semi-solid mass separating out is ground with the smallest the mixture is maintained at about 25 0., the whole being briskly stirred. After 2 hours the nitrogen evolution is complete. From the brown colored reaction mixture the acetone is driven oflf with steam. The residue is taken up in'ether. the ether distilled off and the remaining oil, for removal of any unchanged cinnamic aldehyde present, is stirred for one hour at room temperature with a solution of 120 grams oi. crystalline sodium sulphite and 35 grams oi! sodium carbonate in 750 ccs. or water. The oil permeated by crystals is ground with a little ether and the separated crystals filtered with suction. From the mother liquor there are obtained by distillation in high vacuum further quantities of the reaction product in oily iorm, which by treatment with petrol ether give crystalline a-pchlorophenyl cinnamic aldehyde. The combined portionsare'recrystallised from benzine or acetic acid and are then produced in colorless leaflets oi melting point -86 C. In concentrated sulphuric acid only aldehyde is soluble, though diflicultly, with intensive green blue color.

01 course, many changes and variations in the reaction conditions etc. may be made by those skilled in the art in accordance with the principlm set forth herein and in the claims annexed hereto.

What I claim is:

1. Process for the production of aryl derivatives of unsaturated compounds, which oomprises reacting an a-p-unsaturated carbonyl compound oi' non-quinone character and containing a hydrogen atom' on the carbon atom adiacent to the carbonyl group with a member or the group consisting of aromatic diazonium salts and compounds yielding such salts. in weekly acid solution and at such temperatures that the diazo group is split of! as nitrogen.

2.'Compounds or the formula wherein x is a salt-forming roup or the class consisting of carboxylic and sulionic groups.

3. The compound or the iormula 6. Process as claimed in claim 1, wherein the reaction products obtained by interaction with 'aryldiazonium haloids are treated with agents splitting oi! hydrogen halide.

'7. Process as claimed in claim 1,- wherein the .starting carbonyl compound has an aliphatic double bond.

8. Process as claimed in claim 1, wherein in- 6 stead of the aromatic diazonium compounds,

acylnitrosamines are employed.

HANS 

